You need the original Emergency 4 (or 911: First Responders ) game installed first—this is a mod, not a standalone game.
Overview The Los Angeles Mod (v3.1.5) is widely considered the gold standard for Emergency 4 (also known as 911: First Responders ). This free, fan-made overhaul transports the game from the generic German setting to the streets of Los Angeles, featuring LAPD, LAFD, LASD, and CHP units. Emergency 4 Los Angeles Mod 3.1.5 Download --FREE